Please don't be too offended. The whole quote goes 'The Right can't write and the Left can't talk'. The examples you gave show that the Right can't write, although I would add Ayn Rand.Do you really think of your political opponents as people being too stupid to write well?
The quote goes to Joe Bageant from his excellent collection of blog posts "Deer Hunting With Jesus". Which I would recommend to everyone, of every political persuasion. Some of them may be a bit dated after 20yrs but it remains a great insight into US culture. (Lynndie English...wow).
Born a Lefty he set out to understand why 'rednecks' (his people) largely voted Republican. Just as Aus battlers voted for Howard. He concluded while Democrats on the left offered a much better deal to the rednecks they could not break through because of their inability to talk. The Left always comes across as too preachy. Something we have seen morph into the thoroughly rotten 'woke' agenda.